Date: Sat, 13 Apr 2019 12:33:11 +0200 (CEST)
From: Jacek Lipkowski <sq5bpf@lipkowski.org>
To: rsgb_lf_group@blacksheep.org
In-Reply-To: <alpine.DEB.2.11.1904120916210.22616@mailn.lipkowski.org>
Message-ID: <alpine.DEB.2.11.1904131208470.22616@mailn.lipkowski.org>
References: <1652663722.1033558.1554575549616.ref@mail.yahoo.com> <1652663722.1033558.1554575549616@mail.yahoo.com> <5CA90E98.2070707@posteo.de> <8c46744b-f60a-ca91-f60f-97a2f5f7b11f@abelian.org> <5CA931D4.6050908@posteo.de> <83eece37-ae11-b2fd-917c-ad29c350695b@abelian.org>
 <5CA9BD98.2030002@posteo.de> <alpine.DEB.2.11.1904071231190.22616@mailn.lipkowski.org> <5CAA1D1D.8070204@posteo.de> <alpine.DEB.2.11.1904082241090.22616@mailn.lipkowski.org> <5CABBF99.6010502@posteo.de> <alpine.DEB.2.11.1904090832200.22616@mailn.lipkowski.org>
 <5CAD944C.7050006@posteo.de> <alpine.DEB.2.11.1904112110350.22616@mailn.lipkowski.org> <5CAFA72A.10602@posteo.de> <alpine.DEB.2.11.1904120916210.22616@mailn.lipkowski.org>
User-Agent: Alpine 2.11 (DEB 23 2013-08-11)
MIME-Version: 1.0
Subject: Re: ULF: EbNaut message transmitted from ground loop
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org

i'm still trying to find improved decoding parameters for Stefan's last 
transmission, so that i can use them in later tests on ULF.

so after trying a few thousand more parameter combinations, results so 
far are:

vtcat -p < stefan_2970_1  | vtfilter -a th=3 -h bp,f=2970,w=2200 > pliktmp15

vtblank -v  -d0.0007 -a20 -t 50 <pliktmp15 |  vtmult -f 2970.1 | vtresample -r 240 |    vtresample -r 10 |vtraw -oa  | ebnaut  -dp16K21A -r10 -c2 -v -k16 -S6 -N7  -PS -L 50000


gives:

vtblank: selected channel: 1 = -:1
vtblank: channels: 1, sample_rate: 48000
vtblank: hfactor: 0.000e+00
vtblank: afactor: 20.000
initial reference phase -84.0 amplitude 7.583e-04
phase   0    0    0    0    0
vtblank: end of input
vtblank: dropsum 0 65905643, nfp 359999999
vtblank: dropfactor 0 1.831e-01

found rank 18241 ber 4.1747e-01 Eb/N0 -1.6 M -2.109796181e-02 ph 0 0,0,0,0 [DK7FC/P]
carrier phase: -16.9 deg
carrier Eb/N0: -0.2 dB
carrier Es/N0: -15.11 dB
carrier S/N: 15.85 dB in 133.5 uHz, -22.89 dB in 1Hz, -56.87 dB in 2.5kHz
elapsed 123


found rank 5336 ber 4.3029e-01 Eb/N0 -3.1 M -2.148468420e-02 ph 4 -30,-30,-30,-30 [DK7FC/P]
carrier phase: 13.1 deg
carrier Eb/N0: -0.2 dB
carrier Es/N0: -15.11 dB
carrier S/N: 15.85 dB in 133.5 uHz, -22.89 dB in 1Hz, -56.87 dB in 2.5kHz
elapsed 149

found rank 13104 ber 4.2468e-01 Eb/N0 -2.4 M -2.153512836e-02 ph 16 0,0,-30,-30 [DK7FC/P]
carrier phase: -0.5 deg
carrier Eb/N0: -0.4 dB
carrier Es/N0: -15.32 dB
carrier S/N: 15.65 dB in 133.5 uHz, -23.10 dB in 1Hz, -57.08 dB in 2.5kHz
elapsed 225


false decode:

found rank 5437 ber 4.1346e-01 Eb/N0 -1.2 M -2.160945535e-02 ph 26 30,30,60,60 [OPLWL !]
carrier phase: -5.6 deg
carrier Eb/N0: -0.3 dB
carrier Es/N0: -15.25 dB
carrier S/N: 15.72 dB in 133.5 uHz, -23.03 dB in 1Hz, -57.01 dB in 2.5kHz
elapsed 287


found rank 2809 ber 4.2468e-01 Eb/N0 -2.4 M -2.200631052e-02 ph 40 0,-30,0,-30 [DK7FC/P]
carrier phase: -2.0 deg
carrier Eb/N0: -0.2 dB
carrier Es/N0: -15.12 dB
carrier S/N: 15.84 dB in 133.5 uHz, -22.90 dB in 1Hz, -56.88 dB in 2.5kHz
elapsed 375


jacek


On Fri, 12 Apr 2019, Jacek Lipkowski wrote:

> Date: Fri, 12 Apr 2019 10:11:06 +0200 (CEST)
> From: Jacek Lipkowski <sq5bpf@lipkowski.org>
> Reply-To: rsgb_lf_group@blacksheep.org
> To: rsgb_lf_group@blacksheep.org
> Subject: Re: ULF: EbNaut message transmitted from ground loop
> 
> On Thu, 11 Apr 2019, DK7FC wrote:
>
>> That's great! Amazing! 976 km distance in the ULF range!
>> A decode at 15.63 dB carrier S/N.
>
> Improved parameters:
>
> sq5bpf@jitter:/stuff2/sq5bpf/vlf_stefan2$  vtcat -p < stefan_2970_1  | 
> vtfilter -a th=4 -h bp,f=2970,w=2300 > pliktmp7
>
> sq5bpf@jitter:/stuff2/sq5bpf/vlf_stefan2$ vtblank -v  -d0.0007 -a22 -t 70 < 
> pliktmp7 |  vtmult -f 2970.1 | vtresample -r 240 |    vtresample -r 10 
> |vtraw -oa  | ebnaut  -dp16K21A -r10 -c2 -v -k16 -S6 -N7  -PS -L 50000
>
>
> vtblank: selected channel: 1 = -:1
> vtblank: channels: 1, sample_rate: 48000
> vtblank: hfactor: 0.000e+00
> vtblank: afactor: 22.000
> initial reference phase 88.1 amplitude 8.289e-04
> phase   0    0    0    0    0
> vtblank: end of input
> vtblank: dropsum 0 50041841, nfp 359999999
> vtblank: dropfactor 0 1.390e-01
> phase   1  180  180  180  180
> found rank 6348 ber 4.2147e-01 Eb/N0 -2.0 M -2.316530794e-02 ph 1 
> 180,180,180,180 [DK7FC/P]
> carrier phase: -10.7 deg
> carrier Eb/N0: -0.3 dB
> carrier Es/N0: -15.26 dB
> carrier S/N: 15.70 dB in 133.5 uHz, -23.04 dB in 1Hz, -57.02 dB in 2.5kHz
> elapsed 98
> phase   2   30   30   30   30
>
> I'm still trying to find better decoding parameters. For now i'm trying a 
> bandpass filter with varying widths, and trying to find the best noiseblanker 
> parameters for each of these filters. A 2300Hz filter seems best for now. I'm 
> trying different bandwidths in 100Hz increments, started at 1800Hz, currently 
> i'm trying 2500Hz and 2600Hz, about 840 different vtblank parameters are 
> tried per each bandwidth. Later i will repeat the tests with different th 
> parameter, preset notches in the passband etc.
>
> Unfortunately the search is done on two workstations with i7-7700 (8 cores) 
> at 4GHz (this is due to intel turbo-boost, these are 3.6GHz cpus). I will try 
> to set up a proper htcondor cluster later with more machines.
>
>> Can you describe your RX antenna and location/position of it?
>
> This is an e-field antenna: BF862 amplifier, the e-probe is a big can 
> (probably around 20cm height, 13cm diameter). The antenna is located on the 
> roof of a 4-story building in Warsaw. Care was taken to use the best 
> engineering practices (zip-ties, duct tape etc).
>
> The antenna location is bad, but i've tried not to add more noise than it 
> already has by eliminating ground loops, isolating from noisy power supplies 
> etc.
>
>> Thank you for your work!  I will try to use your parameters and then we see 
>> the digital loss of the vorbis path.
>> It is a good set of data to 'play' with, because this 
>> distance/frequency/mode has never been done by radio amateurs before.
>
> I can make the raw data avaliable in case anyone is interested.
>
>> A first detection/decode DL > SP.
>> 
>> Eventually i'll do more experiments this weekend. Let's hope for a suitable 
>> wx. The last days have not been really quiet ;-)
>> 
>> And BTW, when is your next transmission together with Marcin?
>
> There is no time set yet. I need to finish my tx first.
>
>> Another thing: Sometimes i git better results when using vtfilter -h lp... 
>> -h hp... instead of vtfilter -h bp... because the edges are a bit smoother. 
>> Also it can improve the SNR to place the center frequency of the filter not 
>> to the TX frequ ency but some 100 Hz up or down, depending on the noise 
>> distribution.
>
> I've tried the hp/lp combination but usually it wasn't better.
>
> What works is to look at the spectrogram and notch out the noise peaks in the 
> filter passband.
>
>> PS: I remember you asked a few times if i can go lower than 5170 Hz. Now we 
>> are there :-)
>
> Yes! But don't stop until you get to DC :)
>
> VY 73
>
> Jacek / SQ5BPF
>
>